Take equal parts of I and II and 6 parts of water. If more contrast is needed, take equal parts of I and II and 3 parts of water, with 5 drops to the ounce of a 1/10 solution of bromide of potassium.

Metol And Hydrochinon Developer.—
I.—Pure hot water80 ounces
Metol 1 ounce
Hydrochinon   1/8 ounce
Sulphite soda, crystals 6 ounces
II.—Pure water80 ounces
Carbonate soda, crystals 5 ounces
To develop, take of
Pure water 2 ounces
Solution No. I 1 ounce
Solution No. II 1 ounce
Metol-bicarbonate Developer.
Metol 1 ounce
In water60 ounces
Then add
Sulphite of soda, crystals 6 ounces
Bicarbonate of soda 3 ounces
To prepare with hydrometer, mix
Sulphite of soda solution, testing 7530 ounces
Bicarbonate of soda solution, testing 5030 ounces
Metol 1 ounce
Dissolved in 12 ounces water.
Ferrous-oxalate Developer.
I.—Oxalate of potash 8 ounces
Water30 ounces
Citric acid60 grains
Citrate of ammonia solution 2 ounces
II.—Sulphate of iron 4 ounces
Water32 ounces
Sulphuric acid16 drops
III.—Citrate of ammonia solution saturated.

Dissolve 1 ounce citric acid in 5 ounces distilled water, add liquor ammonia until a slip of litmus paper just loses the red color, then add water to make the whole measure 8 ounces.

Add 1 ounce of II to 2 of I, and 1/2 ounce of water, and 3 to 6 drops of 10 per cent solution bromide potassium.

To develop, first rinse developing dish with water, lay film or plate down, and flow with sufficient developer to well cover. Careful attention must be given to its action, and when detail is just showing in the face, or half-tone lights in a view, pour off developer, and well wash the film before placing in the fixing bath.